Delayed release pharmaceutical composition of pantoprazole and process for formulation thereof

ABSTRACT

The present invention discloses stable delayed release multiparticulate powder for oral suspension of proton pump inhibitor compounds comprising: a) a core with an effective amount of proton pump inhibitor and at least one or more pharmaceutical excipients, b) at least one water-soluble seal coating over core c) at least one enteric coating layer over the seal coat wherein the said core comprises disintegrant (0-10%) and/or surfactant (0-2%) w/w of core. The prior art discloses restrictive formulation technique and suggest high amount of various excipients to achieve desired technical attributes. The prepared test formulations exhibited desired pharmaceutical technical attributes like drug release, assay, stability, no polymorphic change, reduced sticking to nasogastric and gastronomy tubes, and packaging material.

FIELD OF THE INVENTION

This invention in general relates to stable pharmaceutical compositioncomprising acid labile compounds or their pharmaceutically acceptablesalts, esters, solvates, polymorphs, enantiomers or mixtures thereof. Inparticular, the present invention discloses a stable solid oral delayedrelease multiparticulate pharmaceutical composition comprisingbenzimidazole derivatives and process for preparing the same.

BACKGROUND OF THE INVENTION

Proton pump inhibitors (PPIs) are agents having powerful inhibitoryaction against H+/K+-adenosine triphosphate (ATP) and prevent secretionof gastric acid. For example, Pantoprazole sodium is a proton pumpinhibitor and is pharmaceutically used in short-term treatment (7 to 10days) of Gastroesophageal Reflux Disease (GERD) associated with ahistory of erosive esophagitis as well as for the treatment ofpathological hypersecretory conditions including Zollinger-EllisonSyndrome in adults. These Proton pump inhibitors are generally reportedto be acid labile compounds/derivatives.

Pantoprazole sodium, is a substituted benzimidazole derivative and ischemically known as sodium5-(difluoromethoxy)-2-[[(3,4-dimethoxy-2-pyridinyl)methyl]sulfinyl]-1Hbenzimidazole. In various marketed formulations crystallinesesquihydrate polymorphic form is used. Sodium5-(difluoromethoxy)-2-[[(3,4-dimethoxy-2-pyridinyl)methyl]sulfinyl]-1Hbenzimidazole sesquihydrate is represented by the following formula:

Following formulations of Pantoprazole sodium are approved in the USA:(I) 20 & 40 mg delayed release tablets(II) i.v. infusion formulation (Eq 40 mg base/vial)(III) Delayed release granules for oral suspension (Eq 40 mg base)

Patent publication U.S. Pat. No. 4,758,579 is assigned to Nycomed whichcovers Pantoprazole as a product.

Pantoprazole sodium sesquihydrate delayed release granules for oralsuspension are marketed in the USA under the brand name PROTONIX® andcontain crospovidone, hypromellose, methacrylic acid copolymer,microcrystalline cellulose, polysorbate 80, povidone, sodium carbonate,sodium lauryl sulfate, talc, titanium dioxide, triethyl citrate, andyellow ferric oxide as the inactive ingredients. For patients havingdifficulty in swallowing, such as pediatric and geriatric patients, oralliquid formulations such as suspension is the preferred dosage form.Pantoprazole sodium sesquihydrate delayed release granules for oralsuspension can be administered by sprinkling the granules on oneteaspoonful of applesauce or empty granules into a small cup or teaspooncontaining one teaspoon of apple juice and consume this within 10minutes of preparation.

Patent publication U.S. Pat. No. 5,997,903 is assigned to Byk Guldendiscloses oral delayed release tablet dosage forms of Pantoprazole.

Patent publication U.S. Pat. No. 8,865,212 is assigned to JubilantGenerics Ltd. discloses non-multiple unit pellet system (MUPS) of anacid labile benzimidazole derivative in tablet dosage forms devoid ofdisintegrant.

Patent publications U.S. Pat. Nos. 7,544,370, 7,550,153, 7,553,498 and7,838,027 are assigned to Wyeth and listed in Approved Drug Productswith Therapeutic Equivalence Evaluations (Orange Book) disclosemultiparticulate formulation of Pantoprazole. As per the disclosure ofthese patent publications, the benzimidazole derivatives employed asproton pump inhibitors are easily destroyed in the acid milieu and thusare difficult to formulate for oral administration. These patentpublications highlight various formulation challenges associated withmultiparticulate formulation of Pantoprazole such as, stability issuesat room temperature, inappropriate release under acid conditions andadherence to the intestinal walls, nasogastric and gastronomy tubes. Asper these patent publications, the desired formulation was achieved byessentially using the following proportion of pharmaceutical excipients:

Ingredients Range % w/w of the core Pantoprazole sodium about 45% 45.24Microcrystalline cellulose about 25 to 30% 27.25 Polysorbate 80 about 4to 6% 5 Crospovidone about 14 to 16% 15 Hypromellose about 0.5 to 2% 1Sodium carbonate about 5 to 8% 6.5

Multiparticulate formulations of proton pump inhibitor are prepared bymixing disintegrant(s) and surfactant for consistent and satisfactorydissolution of drug from the dosage form. Disintegrants are oftenconsidered as most important, as they ensure the break-up of the dosageform into smaller fragments upon ingestion, to allow the onset of drugdissolution and eventual absorption. Disintegrants are often associatedwith promoting moisture penetration into the matrix of core of thedosage form to initiate the disintegration process. The disintegrationprocess can mechanistically be subdivided into stages, breakdown intocoarse aggregates and subsequent deaggregation into fine primaryparticles which subsequently increases the surface area.

Surfactants used in enteric coated dosage forms, provide betterwettability and enhance the solubility of the drug, which improves thedissolution property. On the other hand, higher amount of surfactant canalso cause gastric irritation. As per patent publication listed inApproved Drug Products with Therapeutic Equivalence Evaluations (OrangeBook) by the innovator for the desired technical attributes,disintegrant is used in the range of 14-16% w/w and surfactant is usedin the range of 4-6% w/w, which is very high.

Surprisingly, it is found by the inventors of the present invention thatmultiparticulate compositions of benzimidazole compounds, particularlyPantoprazole compositions, can be prepared by varying the amount ofessential excipients like disintegrant and surfactant. Further, byavoiding the higher amount of disintegrant and/or using lesser amount ofsurfactant desired pharmaceutical technical attributes were achievedlike drug release, assay, stability, no polymorphic change, reduced orno sticking to nasogastric and gastronomy tubes, and packaging material.

SUMMARY OF THE INVENTION

The present invention relates to a stable solid oral delayed releasemultiparticulate pharmaceutical composition prepared by varying theamount of essential excipients like disintegrant and/or surfactant,which exhibited desired pharmaceutical technical attribute comparable tothe innovator's marketed product (PROTONIX® suspension). Preferably, byavoiding the higher amount of disintegrant and/or using lesser amount ofsurfactant, desired pharmaceutical technical attributes were achievedlike drug release, assay, stability, no polymorphic change, reduced orno sticking to nasogastric and gastronomy tubes, and packaging material.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graphical depiction of % drug release (dissolution profile)of commercially available Pantoprazole delayed release powder for oralsuspension “Protonix®” from Wyeth and Pantoprazole delayed releasepowder for oral suspension of example I-III.

FIG. 2 is a characteristic X-ray diffraction pattern of input API(Pantoprazole sodium sesquihydrate), the packaged multiparticulatepowder formulation both at initial and accelerated stability condition.

DESCRIPTION OF THE INVENTION

The present invention can be more readily understood by reading thefollowing detailed description of the invention and study of theincluded examples.

As used herein, the term “composition”, as in pharmaceuticalcomposition, is intended to encompass a drug product comprisingPantoprazole or its pharmaceutically acceptable salts, esters, solvates,polymorphs, enantiomers or mixtures thereof, and the other inertingredient(s) (pharmaceutically acceptable excipients). Suchpharmaceutical compositions are synonymous with “formulation” and“dosage form”. Pharmaceutical composition of the invention include, butis not limited to, pellets, granules, beads, minitabs, spherules,beadlets, microcapsules, millispheres, microspheres and the like.Preferably, the pharmaceutical composition refers to spheres. Morepreferably, the pharmaceutical composition refers to delayed releasepellets/spheres for oral suspension, wherein granules and powders fororal suspension are alike. The term “multiparticulate” means a pluralityof discrete or aggregated particles, pellets, beads, spheres orspheroids or mixture thereof, irrespective of their size, shape ormorphology. Each individual particle, pellet, bead, spheres or spheroidsmaking up a multiparticulate is referred to herein, as a “particulate.”Preferably the multiparticulates are spheroids prepared by extrusionspheronization.

“Acid labile benzimidazole” as used herein refers to benzimidazolecompounds of therapeutic interest whose half-life is less than 10minutes in an aqueous solution, that has a pH less than 4, for examplePantoprazole, Lansoprazole, Rabeprazole, Omeprazole, Timoprazole,Picoprazole and the like.

“Pantoprazole” as used herein refers to the free acid form, its salts,esters, solvates, polymorphs, enantiomers or mixtures thereof.Preferably, the salt of Pantoprazole used here is Pantoprazole sodium.More preferably, the salt of Pantoprazole used here is Pantoprazolesodium sesquihydrate.

The term “core” as used herein refers to pellets/spheres comprising adrug, at least a diluent, an alkaline agent, wherein the core alsocomprises a varying amount of disintegrant and/or surfactant.

The term “excipient” means a pharmacologically inactive component suchas a diluent, lubricant, surfactant, carrier, or the like. Theexcipients that are useful in preparing a pharmaceutical composition aregenerally safe, non-toxic and are acceptable for veterinary as well ashuman pharmaceutical use. Reference to an excipient includes both oneand more than one such excipient. Co-processed excipients are alsocovered under the scope of present invention. Further, excipient may bein the form of powders or in the form of dispersion. Combination ofexcipients performing the same function may also be used to achievedesired formulation characteristics.

“Delayed release” as used herein refers to a solid dosage, whichreleases a drug (or drugs) at a time other than promptly afteradministration. For the purpose of this invention enteric-coatedarticles are delayed release dosage forms.

The term “substantially free Surfactant” as used herein refers to theamount which is in range from 0-2% w/w by total weight of core.

The term “substantially free disintegrant” as used herein refers to 0-1%w/w by total weight of the core.

As used herein, the term “about” means±approximately 10% of theindicated value.

The term “w/w” as used herein refers the total weight of the corecomposition.

In another embodiment, the present invention includes a solid oralmultiparticulate pharmaceutical composition comprising Pantoprazole orits pharmaceutically acceptable salts, esters, solvates, polymorphs,enantiomers or mixtures thereof.

In an another embodiment of the invention, the solid oral delayedrelease multiparticulate pharmaceutical composition comprises apharmacologically effective amount of proton pump inhibitor, preferablyPantoprazole or its pharmaceutically acceptable salt, esters, solvates,polymorphs, enantiomers or mixtures thereof, wherein the composition issubstantially free of disintegrant and/or surfactant.

In another embodiment of the invention, the delayed releasemultiparticulate powder for oral suspension comprising:

-   a) a core comprising an effective amount of Pantoprazole or its    pharmaceutically acceptable salts, at least one diluent and an    alkaline agent,-   b) at least one seal coating layer over core-   c) at least one enteric coating layer over the seal coat-   d) and optionally an outer seal coating layer    wherein the said core is substantially free of disintegrant (0-1%    w/w) and/or surfactant (0-2% w/w).

Yet another embodiment of the present invention, the delayed releasemultiparticulate powder for oral suspension prepared by extrusionspheronization process comprising:

-   a) a core comprising an effective amount of Pantoprazole or its    pharmaceutically acceptable salts and at least one diluent and an    alkaline agent,-   b) at least one seal coating layer over core and-   c) at least one enteric coating layer over the seal coat    wherein the said core comprises of disintegrant from 1-10% w/w    and/or surfactant from 0-2% w/w.

In another embodiment of the invention, the delayed releasemultiparticulate powder for oral suspension prepared by extrusionspheronization process comprising:

-   a) a core comprising an effective amount of Pantoprazole or its    pharmaceutically acceptable salts and at least one diluent and an    alkaline agent,-   b) at least one seal coating layer over core and-   c) at least one enteric coating layer over the seal coat    wherein the said core comprises of disintegrant from 1-10% w/w and    free of surfactant.

Yet another embodiment of the present invention, the delayed releasemultiparticulate powder for oral suspension of Pantoprazole or itspharmaceutically acceptable salts comprising:

-   a) a core comprising an effective amount of Pantoprazole or its    pharmaceutically acceptable salts, at least a diluent, and an    alkaline agent,-   b) at least one water-soluble seal coating layer, and-   c) at least one enteric coating layer over the seal coat    wherein the said core comprises of disintegrant in the range of from    1-10% w/w and surfactant is in an amount from 0-2% w/w of the core.

Yet another embodiment of the present invention, the delayed releasemultiparticulate powder for oral suspension of Pantoprazole or itspharmaceutically acceptable salts comprising:

-   a) a core comprising an effective amount of Pantoprazole or its    pharmaceutically acceptable salts, at least a diluent, a surfactant    and an alkaline agent,-   b) at least one water-soluble seal coating layer, and-   c) at least one enteric coating layer over the seal coat and    optionally an outer seal coating layer    wherein the said core comprises disintegrant in an amount of less    than 14% w/w and/or surfactant in an amount ranging from 0-2% w/w.

In yet another embodiment of the present invention, the solid oraldelayed release multiparticulate pharmaceutical composition comprises apharmacologically effective amount of proton pump inhibitor, preferablyPantoprazole or its pharmaceutically acceptable salt, esters, solvates,polymorphs, enantiomers or mixtures thereof present in an amount ofabout 30% w/w to about 70% w/w of core, preferably about 50% w/w toabout 70% w/w of core, more preferably about 40% w/w to about 60% w/w ofthe core and a process for preparing the same.

In yet another embodiment of the invention, the solid oral delayedrelease multiparticulate pharmaceutical composition comprises of a coreof a pharmacologically effective amount of Pantoprazole or itspharmaceutically acceptable salt, esters, solvates, polymorphs,enantiomers or mixtures thereof and one or more other excipients,wherein a seal coat of water soluble polymer is present in between thecore and the enteric coat, wherein the water-soluble polymer is selectedfrom Hydroxypropyl cellulose, Hydroxypropyl methylcellulose.

In yet another embodiment of the invention, the solid oral delayedrelease multiparticulate pharmaceutical composition comprises of a coreof a pharmacologically effective amount of Pantoprazole or itspharmaceutically acceptable salt, esters, solvates, polymorphs,enantiomers or mixtures thereof and one or more other excipients,wherein the composition is devoid of a seal coat in between the core andthe enteric coat. In yet another embodiment of the invention, the solidoral delayed release multiparticulate pharmaceutical compositioncomprises of about 5 mg to about 240 mg of Pantoprazole or itspharmaceutically acceptable salts, esters, solvates, polymorphs,enantiomers or mixtures thereof.

Another embodiment of the present invention encompasses a solid oraldelayed release multiparticulate pharmaceutical compositions comprisingPantoprazole or its pharmaceutically acceptable salts, esters, solvates,polymorphs, enantiomers or mixtures thereof from about 30% w/w to about70% w/w of the core, preferably about 50% w/w to about 70% w/w of thecore, more preferably about 40% w/w to about 60% w/w of the core and apharmaceutically acceptable excipient selected from at least one ofdiluent, binder, alkaline agent, glidant, plasticizer and otherpharmaceutical excipients. Combination of excipients performing the samefunction may also be used to achieve desired formulationcharacteristics.

In yet another embodiment of the present invention, delayed releasemultiparticulate powder for oral suspension prepared by extrusionspheronization process comprising:

-   a) a core comprising    -   about 30% w/w to about 70% w/w of Pantoprazole and its        pharmaceutically acceptable salts    -   about 20% w/w to about 60% w/w of a diluent,    -   about 0% w/w to about 2% w/w of a surfactant, and    -   about 2% w/w to about 10% w/w of an alkaline agent,    -   from 0% w/w to 10% w/w of disintegrant-   b) at least one water-soluble seal coating layer and-   c) at least one enteric coating layer over the seal coat and    optionally an outer seal coating layer.

In another embodiment of the present invention, the solid oral delayedrelease multiparticulate pharmaceutical composition of the invention isprepared extrusion spheronization technique. Other formulationtechniques are also contemplated within the scope of the presentinvention.

In another embodiment of the present invention, the solid oral delayedrelease multiparticulate pharmaceutical composition comprisingPantoprazole or its pharmaceutically acceptable salts, esters, solvates,polymorphs, enantiomers or mixtures thereof comprises surfactant in anamount of about 0% w/w to about 4% w/w, preferably in an amount of lessthan 2%.

In another embodiment, the solid oral delayed release multiparticulatecomposition comprising Pantoprazole or its pharmaceutically acceptablesalts, esters, solvates, polymorphs, enantiomers or mixtures thereof,wherein the particle size of pellets/spheres have an average diameter ofabout 0.6 mm to about 1.2 mm; preferably from about 0.7 mm to about 1.0mm.

Another embodiment of the present invention also provides a process forthe preparation of a solid oral delayed release multiparticulatepharmaceutical composition of Pantoprazole or its pharmaceuticallyacceptable salts, esters, solvates, polymorphs, enantiomers or mixturesthereof of, comprising the steps of; (a) dry blending the drug andexcipients, (b) wet granulation (aqueous or non-aqueous) of the mass,(c) extrusion through a screen of defined mesh size to compact the wetmass into cylindrical strands, (d) spheronization of cylindrical strandsin a spheronizer to convert the cylindrical strands into spheres, (e)seal coating of the spheres, (f) enteric coating of the spheres over theseal coating, and (g) optionally coated with an outer seal coat over theenteric coating layer.

In another embodiment of the present invention, the solid oral delayedrelease multiparticulates present in the pharmaceutical compositioncomprising Pantoprazole or its pharmaceutically acceptable salts,esters, solvates, polymorphs, enantiomers or mixtures thereof having abulk density in the range from 0.72 g/ml to 0.82 g/ml and tapped densityin the range from 0.76 g/ml to 0.84 g/ml.

In another embodiment, the solid oral delayed release multiparticulatepharmaceutical composition comprising Pantoprazole or itspharmaceutically acceptable salts, esters, solvates, polymorphs,enantiomers or mixtures thereof, wherein the pellets/spheres exhibited abiphasic dissolution profile, whereby negligible drug release exhibitedin an acid stage and substantial drug release exhibited at buffer stage(pH 6.8).

In another embodiment, the solid oral delayed release multiparticulatepowder for oral suspension comprising Pantoprazole or itspharmaceutically acceptable salts, esters, solvates, polymorphs,enantiomers or mixtures thereof can be administered by sprinkling thepellets/spheres on teaspoonful full of applesauce or apple juice whereinthe composition exhibited stability for at least 10 minutes.

In another embodiment, the solid oral delayed release multiparticulatepharmaceutical composition comprising Pantoprazole or itspharmaceutically acceptable salts, esters, solvates, polymorphs,enantiomers or mixtures thereof are stable at 40° C. and 75% relativehumidity at least for a period of about 1 month.

In yet another embodiment, the solid oral delayed releasemultiparticulate pharmaceutical composition comprising Pantoprazole orits pharmaceutically acceptable salts, esters, solvates, polymorphs,enantiomers or mixtures thereof, are stable at 60° C. for at least 1week.

In further embodiment, the present invention includes method of usingthe enteric coated solid oral delayed release multiparticulatepharmaceutical composition comprising pellets/spheres of Pantoprazole orits pharmaceutically acceptable salts, esters, solvates, polymorphs,enantiomers or mixtures thereof in the treatment of GastroesophagealReflux Disease (GERD) associated with a history of erosive esophagitisas well as for the treatment of pathological hypersecretory conditionsincluding Zollinger-Ellison Syndrome.

Another embodiment of the present invention includes oral delayedrelease multiparticulate pharmaceutical compositions comprisingPantoprazole sodium prepared by using dry granulation, dry blending,extrusion spheronization or wet granulation process. Suitable solventsinclude aqueous or organic solvents. Preferable solvents include, butare not limited to, water, esters such as ethyl acetate; ketones such asacetone; alcohols such as methanol, ethanol, isopropanol, butanol;dichloromethane, chloroform, dimethyl acetamide (DMA), dimethylsulfoxide (DMSO), ether, diethyl ether and combinations thereof.Preferably, the solvent used during wet mass preparation is water.

In another embodiment of the invention, wet granulation can be performedusing Rapid mixer granulator, Fluid bed granulator, Planetary mixer andthe like; dry blending can be performed in V-blender or key blender;spheronization can be performed using Fuji Paudal spheronizer or by anyother method known in the art.

One embodiment of the invention encompasses a delayed releasemultiparticulate composition comprising Pantoprazole or a salt thereofand a pharmaceutically acceptable excipient selected from at least oneof diluent, binder, disintegrant, surfactant, alkaline agent, andglidant.

In another embodiment of the invention, the solid oral delayed releasemultiparticulate pharmaceutical composition comprises less than 4% w/wof surfactant, preferably the composition comprises surfactant in anamount of from 0% w/w to 4% w/w, preferably in an amount of 0-2% w/w ofthe core.

Diluents or fillers are substances which usually provide bulk to thecomposition. Various useful fillers or diluents include, but are notlimited to microcrystalline cellulose, calcium carbonate, calciumphosphate, dibasic anhydrous, calcium phosphate, dibasic dihydrate,calcium phosphate tribasic, calcium sulphate, cellulose powdered,cellulose acetate, compressible sugar, confectioner's sugar, dextrates,dextrose, fructose, lactitol, lactose, magnesium carbonate, magnesiumoxide, maltodextrin, maltose, mannitol, polydextrose, simethicone,sodium alginate, sodium chloride, sorbitol, starch, pregelatinizedstarch, sucrose, trehalose and xylitol, or mixtures thereof. Diluent mayconstitute from about 10% to about 95% by weight of enteric coatedpellets/spheres.

Binders impart cohesiveness to formulation. Various useful bindersinclude, but are not limited to hypromellose, acacia, alginic acid,carbomer, sodium carboxymethylcellulose, dextrin, ethylcellulose,gelatin, glucose, guar gum, hydroxypropylcellulose, maltose,methylcellulose, povidone, copovidone, starch, polyvinyl alcohol orpolyethylene oxide, or mixtures thereof. The binder may constitute fromabout 1% to about 20% by weight of enteric coated pellets/spheres.

Glidants improve flowability and accuracy of dosing. Since the presentinvention relates to an oral pharmaceutical composition, it isimperative to use glidant(s) to achieve desirable flowability of theactive. Glidants used in the composition include, but are not limitedto, tribasic calcium phosphate, calcium silicate, cellulose, powdered,colloidal silicon dioxide, magnesium silicate, magnesium trisilicate,starch and talc or mixtures thereof.

Surfactants or surface-active agents improve wettability of the dosageform and/or enhance its dissolution. Surfactants contemplated in thepresent invention include but are not limited to anionic surfactants,amphoteric surfactants, non-ionic surfactants and macromolecularsurfactants. Suitable examples of anionic surfactants include but arenot limited to sodium lauryl sulphate, sodium cetyl stearyl sulphate orsodium dioctyl sulphosuccinate etc. Suitable example of an amphotericsurfactant include but is not limited to lecithin. Suitable examples ofnon-ionic surfactants include but is not limited to cetyl alcohol,stearyl alcohol, cetyl stearyl alcohol, cholesterol, sorbitan fatty acidesters such as sorbitan mono-oleate, polyoxyethylene sorbitan fatty acidesters such as polysorbate 80, polysorbate 20, polyoxyethylene fattyacid glycerides such as macrogol 1000 glycerol monostearate,polyoxyethylene fatty acid esters such as polyoxyl 40 stearate,polyoxyethylene fatty alcohol ethers such as polyoxyl 10 oleyl ether,glycerol fatty acid esters such as glycerol monostearate, commerciallyavailable SEPITRAP® 80 or SEPITRAP® 4000 etc. The surfactant mayconstitute from about 0% to about 5% by weight of enteric coatedpellets/spheres.

Disintegrants selected from the group comprising crospovidone, modifiedstarches, croscarmellose sodium, sodium starch glycolate, lowsubstituted Hydroxypropyl cellulose and carboxymethylcellulose calcium.These disintegrants are also known as superdisintegrants. Thedisintegrant may constitute from about 0% to about 20% by weight ofenteric coated pellets/spheres.

Alkaline agent may be used to provide a microenvironment of pH above 7around the acid labile benzimidazole derivative. Suitable alkalineagents include, but are not limited to, pharmacologically alkali metal,alkaline earth metal or metal salts of weak acids such as sodiumcarbonate which can be anhydrous or hydrous, calcium carbonate andmagnesium carbonate and the pharmacologically hydroxides and oxides ofalkaline earth and earth metals such as magnesium hydroxide andmagnesium oxide. The alkaline agent may constitute from about 0% toabout 10% by weight of enteric coated pellets/spheres.

In another embodiment, the Pantoprazole delayed releasemultiparticulates of the present invention comprise of a spheroid corecomprising about 30% w/w to about 70% w/w of Pantoprazole or itspharmaceutically acceptable salts, esters, solvates, polymorphs,enantiomers or mixtures thereof; at least one diluent present in anamount of less than about 25% w/w or more than about 30% w/w of thecore; at least one binder present in an amount of less than about 0.5%w/w or more than about 2% w/w of the core; surfactant optionally presentin an amount of less than about 2% w/w of the core; water present in asufficient amount; an enteric coat on the core comprising a copolymer ofmethacrylic acid present in an amount of less than about 15% or morethan about 45% by weight of the composition; wherein said delayedrelease multiparticulates have an average diameter of about 0.6 mm toabout 1.2 mm. In an embodiment of the present invention, additionalPantoprazole polymorphs may be generated during manufacturing of theformulation, which may reduce the bioavailability of the drug. Thepresent invention includes a solid oral dosage form comprisingPantoprazole sodium sesquihydrate wherein, the polymorphic state isidentical in the finished dosage form as the input active ingredient,both at initial and accelerated stability study.

The final formulations may be coated or uncoated. For coating,additional excipients such as film-forming polymers, plasticizers,antiadherents and opacifiers are used.

Various water-soluble polymers are used to form a barrier/seal or filmover the core. Examples include but are not limited to cellulosederivatives such as soluble alkyl- or hydroalkylcellulose derivativessuch as methylcellulose, hydroxymethyl cellulose, hydroxyethylcellulose, hydroxypropyl cellulose, hydroxymethylethyl cellulose,hydroxypropyl methylcellulose, sodium carboxymethyl cellulose, etc.,acidic cellulose derivatives, dextrins, starches and starch derivatives,polymers based on carbohydrates and derivatives thereof, natural gumssuch as gum Arabic, xanthans, alginates, polyacrylic acid, polyvinylalcohol, polyvinyl acetate, polyvinylpyrrolidone, chitosan andderivatives thereof, shellac and derivatives thereof, waxes and fatsubstances. If desired, the films may contain additional adjuvants forcoating such as plasticizers, polishing agents, colorants, pigments,antifoaming agents, opacifiers, antisticking agents, and the like.

Various seal coating polymers include but are not limited topolyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol,Hydroxypropyl methylcellulose and Hydroxypropyl cellulose.

In another embodiment of the invention, enteric coating polymerssuitable for use in the present invention include, but are not limitedto, cellulose acetate phthalate (CAP), cellulose acetate trimellitate(CAT), hydroxypropylmethylcellulose phthalate (HPMCP),hydroxypropylmethylcellulose acetate succinate (HPMCAS),hydroxypropylcellulose acetate phthalate (HPCAP),hydroxypropylmethylcellulose acetate phthalate (HPMCAP), ethylcellulose(EC), polyvinyl acetate phthalate methylcellulose acetate phthalate(MCAP) and methacrylic acid copolymers or its derivatives. Methacrylicacid copolymers or its derivatives are available under various tradenames such as EUDRAGIT®, Acryl-EZE®, Eastacryl®, and Kollicoat® fromEvonik Industries, Colorcon, Eastman Chemical and BASF Fine Chemicalsrespectively. Preferably, enteric coating polymer suitable for use inthe present invention is Eudragit L30D-55.

In another embodiment the present invention includes particle size offree drug particulate form of Pantoprazole or its pharmaceuticallyacceptable salts, esters, solvates, polymorphs, enantiomers or mixturesthereof, wherein particle diameter at 90% cumulative volume (d₉₀) isless than about 100 μm, preferably less than 50 μm. Particle diameter atX % cumulative Particle size reduction can be performed by techniquesincluding but not limited to fluid energy milling, ball milling, colloidmilling, roller milling, hammer milling and the like. Particle size andparticle size distribution can be measured by techniques such as Laserlight scattering (e.g. Malvern Light Scattering), Coulter counter,microscopy and the like.

In yet another embodiment of the invention, the solid oral Pantoprazoledelayed release multiparticulates are packaged in a foil, pouch, capsuleor other suitable package. The delayed release multiparticulate oraldosage form prepared by the above process can be subjected to in vitrodissolution evaluation according to Test 711 “Dissolution” in the UnitedStates Pharmacopoeia 37, United States Pharmacopoeial Convention, Inc.,Rockville, Md., 2014 (“USP”) to determine the rate at which the activesubstance is released from the dosage form, and the content of theactive substance can be determined in solution by high performanceliquid chromatography. When comparing the test and reference products,dissolution profiles should be compared using a similarity factor (f₂).The similarity factor is a logarithmic reciprocal square roottransformation of the sum of squared error and is a measurement of thesimilarity in the percent (%) of dissolution between the two curves.f ₂=50·log {[1+(1/n)Σ_(t=1) ^(n)(R _(t) −T _(t))²]^(−0.5)·100}

Two dissolution profiles are considered similar when the f₂ value isequal to or greater than 50.

In another embodiment, solid oral delayed release multiparticulatepharmaceutical composition of the present invention exhibited biphasicdrug release whereby after two hours 0 to 5% of Pantoprazole sodiumsesquihydrate is released in 750 ml of 0.1 N Hydrochloric Acid (acidstage) solution, sampling at 60, 90 and 120 minutes and not less than75% of Pantoprazole sodium sesquihydrate is released in 1000 ml 0.05 MTribasic Sodium Phosphate pH 6.8 buffer (Add 250 ml of 0.2 mM TribasicSodium Phosphate after completion of acid stage), sampling at 10, 20,30, 45 and 60 minutes (Office of Generic Drugs dissolution database)using a USP II apparatus (paddle) at a temperature of 37±0.5° C. and arotation speed of 100 revolutions per minute. The resultant liquid hasbeen analyzed in UV spectrum at about 289 nm wavelength.

In another embodiment, the solid content of oral delayed releasemultiparticulate pharmaceutical composition of the present inventiondoes not adhere to the intestinal walls, nasogastric and gastronomytubes, and pouch material leading to predictable delivery of the drugproduct to the site of drug release.

Having described the invention with reference to certain preferredembodiments, other embodiments will become apparent to one skilled inthe art from consideration of the specification. The invention isfurther defined by reference to the following examples describing indetail method for the preparation and testing of Pantoprazolepharmaceutical composition. It will be apparent to those skilled in theart that many modifications, both to materials and methods, may bepracticed without departing from the scope of the invention. Followingexamples are set out to illustrate the invention and do not limit thescope of the present invention.

EXAMPLES

The following non-limiting examples are intended to further illustratecertain preferred embodiments of the invention. They are, however notintended to be limiting the scope of the present invention in any way.

Delayed release multiparticulate formulation of Pantoprazole sodium maybe prepared by using quantitative formula as given in table 1:

TABLE 1 Example Composition I II III IV V VI S. No. Ingredients mg/Sachet Core 1 Pantoprazole Sodium Sesquihydrate 45 50    52 45 54   60    equivalent to Pantoprazole 2 Microcrystalline Cellulose (diluent)35 35    31 40 30    22.50  4 Polysorbate 80 (surfactant) 1.00 — — 2.002.00 1.00 5 Sodium lauryl sulfate (surfactant) — 0.50 — — — 0.50 6Crospovidone (disintegrant) 7.5 — — — — 5.00 7 Hypromellose (binder) — —— — — 5.00 9 Hydroxypropyl cellulose 5 8.00 — — 6.00 — 10 Povidone — —5.00 3.00 — — 11 Sodium Carbonate 6.5 6.50 12.00 10.00 8.00 6.00 12Purified Water q.s q.s. q.s. q.s. q.s. q.s. Seal Coating 1 Opadry white— 30.000 — — — 25.00  2 Hypromellose 23.00 — 21.00 21.00 21.00  — 3Povidone — — 1.20 1.20 1.20 — 4 Talc 7.00 — 4.50 6.00 6.00 4.50 5Titanium dioxide — — 3.00 1.45 1.45 2.90 6 Polysorbate 80 — — 0.30 0.300.30 — 7 Iron oxide — — 0.07 0.07 0.07 — 8 Purified water q.s q.s q.sq.s q.s q.s. Enteric Coating 1 Eudragit 63.4 73.00  72.50 55.00 55.00 55.25  2 Talc 21 11.00  11.00 11.00 10.50  10.50  4 Triethyl Citrate6.00 7.00 7.50 5.50 5.50 5.00 5 Sodium lauryl sulfate — 0.14 0.14 0.110.11 0.12 6 Iron oxide —  0.018 0.018 0.014  0.014  0.014 7 PurifiedWater q.s. q.s. q.s. q.s. q.s. q.s. Optional Seal Coating 1 HPMC USP1.50 1.70 1.70 1.25 1.25 1.30 2 Talc 0.4 0.50 0.50 3.00 3.00 2.50 3Purified Water q.s. q.s. q.s. q.s. q.s. q.s. Lubrication 1 Talc 0.240.22 0.22  1.030  1.030  0.250Preferred Method of Manufacture:

Extrusion-spheronization

Brief Manufacturing Process of Example I

-   1. Pantoprazole sodium sesquihydrate and pharmaceutical excipients    were weighed and dispensed in vessel and mixed well;-   2. Sodium carbonate was dissolved in purified water;-   3. Mixture of step 1 was granulated with the solution of step 2 to    prepare wet mass;-   4. Wet mass of step 3 was passed through the extruder-spheronizer;    prepared spheroids were then dried;-   5. Dried spheroids of step 4 were seal coated with water-soluble    polymers and other excipients as mentioned above in Table 1;-   6. Seal coated spheroids of step 5 are then coated with Eudragit    and; optionally coated with an outer seal coating layer.    Note: Examples II-VI are also prepared by using the same    manufacturing process as mentioned in example I with the desired    excipients.

The dosage form as prepared in the above-mentioned process exhibitedbiphasic drug release as mentioned in above section.

The above-mentioned examples I-III of formulation of Pantoprazoledelayed-release powder for oral suspension (initial samples) exhibitedthe in-vitro dissolution profile as shown in Table 2:

TABLE 2 0.1N HCl, 750 ml, USP-II, 100 rpm upto 120 mins followed by0.05M Tribasic sodium phosphate, pH 6.8, 1000 ml, USP-II, 100 rpm (OGDMedia) Batch No. Time point PROTONIX ® Example I Example II Example III(mins) % Release % Release % Release % Release Acid Stage: 0.1N HCl 60 01 0 0 90 0 1 1 0 120 0 1 4 0 Buffer Stage: pH 6.8 10 30 21 22 21 20 9485 84 77 30 102 94 98 90 45 101 96 101 95 60 98 97 101 96

The in-vitro dissolution profile of examples I-III exhibit the % drugrelease as shown in FIG. 1. All the batches exhibited desirable f₂values.

Accelerated stability testing as per the ICH guidelines was conducted onthe pellets/spheres prepared in example I-III at temperature/relativehumidity of 40° C.±2° C./75%±5% for 1 month. Results in terms of amountof Pantoprazole present in the pellets/spheres of the period of storagewere analyzed by validated high performance liquid chromatography methodand the same were presented in the Table 3 below:

TABLE 3 Dissolution (%) by UV Description Assay (%) by HPLC Acid StageBuffer Stage 40° C./75% 40° C./75% 40° C./75% 40° C./75% Example No.Initial RH-1 month Initial RH-1 month Initial RH-1 month Initial RH-1month Example I Off-white Off-white 100.5 99.5 0 0 97 100 Example IIOff-white Off-white 101.5 100.1 0 1 96 102 Example III Off-whiteOff-white 100.5 100.3 0 0 98 101

Further, the XRD data shows that there is no conversion of anypolymorphic form as shown in FIG. 2. This figure shows the X-raydiffraction pattern of input API (Pantoprazole sodium sesquihydrate),the multiparticulate powder for oral suspension sachet of Pantoprazolesodium both at initial and accelerated stability conditions.

In view of the above it is clearly evident that the formulation of theinvention provide in vitro dissolution of Pantoprazole, which iscomparable to Protonix® suspension of Wyeth.

While this invention has been described in detail with reference tocertain preferred embodiments, it should be appreciated that the presentinvention is not limited to those precise embodiments. Rather, in viewof the present disclosure, which describes the current best mode forpracticing the invention, many modifications and variations wouldpresent themselves to those skilled in the art without departing fromthe scope and spirit of the invention.

The invention claimed is:
 1. A delayed release multiparticulate powderfor oral suspension comprising: a) a core comprising an effective amountof Pantoprazole or its pharmaceutically acceptable salts as the soleactive pharmaceutical ingredient, at least one diluent and an alkalineagent, b) at least one seal coating layer over the core, and c) at leastone enteric coating layer over the seal coat, wherein the core is freeof disintegrant and surfactant and the particle size of the Pantoprazoleor its pharmaceutically acceptable salt has a D90 value less than about100 mm, wherein the powder for oral suspension is not a tablet.
 2. Thedelayed release multiparticulate powder for oral suspension as claimedin claim 1, wherein the multiparticulate powder for oral suspension isprepared by extrusion spheronization process.
 3. The delayed releasemultiparticulate powder for oral suspension as claimed in claim 1,wherein the core comprises: about 30% w/w to about 70% w/w of saidPantoprazole and its pharmaceutically acceptable salts about 20% w/w toabout 60% w/w of a diluent, about 2% w/w to about 10% w/w of an alkalineagent.
 4. A process for the preparation of a delayed releasemultiparticulate powder for oral suspension as claimed in claim 1, theprocess comprising the steps of: a) dry blending of the pantoprazole orpharmaceutically acceptable salt and excipients, b) preparing a solutionof an alkaline agent in water, c) granulating the solution of step b)with the blend of step a) to form a granulate; d) extruding thegranulate of step c) to compact the granulate; e) drying the compactedgranulate; f) spheronization of the dried granulate to convert intospheres, g) seal coating of the spheres, h) enteric coating of thespheres over the seal coating, and i) optionally coating with an outerseal coat over the enteric coating layer.
 5. The delayed releasemultiparticulate powder for oral suspension of Pantoprazole or itspharmaceutically acceptable salts as claimed in claim 1, wherein thecomposition is stable for at least 1 month at 40° C. and 75% relativehumidity.
 6. The delayed release multiparticulate powder for oralsuspension of Pantoprazole as claimed in claim 1, wherein the powderexhibits a drug release comparable to the equivalent dose of a currentlymarketed oral pantoprazole delayed release powder for oral suspensionwherein 0-5% drug is released in 0.1N HCL (750 mL) for 2 hours and atleast 75% drug is released within 30 minutes in phosphate buffer (pH6.8; 1000 ml) using a USP II apparatus at 100 rpm.
 7. The delayedrelease multiparticulate powder for oral suspension as claimed in claim1, wherein the diluent is microcrystalline cellulose, and the alkalineagent is sodium carbonate.
 8. The delayed release multiparticulatepowder for oral suspension of Pantoprazole as claimed in claim 1,wherein the diluent is selected from the group comprisingmicrocrystalline cellulose, calcium carbonate, calcium phosphate,dibasic anhydrous, calcium phosphate, dibasic dihydrate, calciumphosphate tribasic, calcium sulphate, cellulose powdered, celluloseacetate, compressible sugar, confectioner's sugar, dextrates, dextrose,fructose, lactitol, lactose, magnesium carbonate, magnesium oxide,maltodextrin, maltose, mannitol, polydextrose, simethicone, sodiumalginate, sodium chloride, sorbitol, starch, pregelatinized starch,sucrose, trehalose and xylitol, or mixtures thereof.
 9. The delayedrelease multiparticulate powder for oral suspension of Pantoprazole asclaimed in claim 1, wherein the alkaline agent is selected from thegroup comprising alkali metal, alkaline earth metal or metal salts ofweak acids such as sodium carbonate which can be anhydrous or hydrous,calcium carbonate and magnesium carbonate and the pharmacologicallyhydroxides and oxides of alkaline earth and earth metals such asmagnesium hydroxide and magnesium oxide.
 10. The delayed releasemultiparticulate powder for oral suspension as claimed in claim 1,wherein the enteric coated cores in the multiparticulate powder have anaverage diameter of about 0.6 mm to about 1.2 mm.
 11. The delayedrelease multiparticulate powder for oral suspension as claimed in claim1, wherein the core further comprises microcrystalline cellulose and/orpovidone.
 12. The delayed release multiparticulate powder for oralsuspension as claimed in claim 1, wherein the core comprisespantoprazole sodium sesquihydrate, microcrystalline cellulose, povidoneand sodium carbonate.
 13. The delayed release multiparticulate powderfor oral suspension as claimed in claim 1, wherein the core comprisesabout 52% (w/w) pantoprazole sodium sesquihydrate, about 31% (w/w)microcrystalline cellulose, about 5% (w/w) povidone and about 12% (w/w)sodium carbonate, wherein the weight percentage is based on the weightof the core.
 14. The delayed release multiparticulate powder for oralsuspension as claimed in claim 1, wherein the seal coat compriseshypromellose, povidone, talc, and titanium dioxide.
 15. The delayedrelease multiparticulate powder for oral suspension as claimed in claim7, wherein the seal coat further comprises polysorbate 80 and/or ironoxide.
 16. The delayed release multiparticulate powder for oralsuspension as claimed in claim 1, wherein the seal coat comprises about70% (w/w) hypromellose, about 4% (w/w) povidone, about 15% (w/w) talc,and about 10% (w/w) titanium dioxide, wherein the weight percentage isbased on the weight of the seal coat.
 17. The delayed releasemultiparticulate powder for oral suspension as claimed in claim 6,wherein the seal coat further comprises about 1% (w/w) polysorbate 80,wherein the weight percentage is based on the weight of the seal coat.18. The delayed release multiparticulate powder for oral suspension asclaimed in claim 1, wherein the enteric coat comprises a methacrylicacid copolymer, talc, triethyl citrate, and sodium lauryl sulfate. 19.The delayed release multiparticulate powder for oral suspension asclaimed in claim 1, wherein the enteric coat comprises about 80% (w/w)of a methacrylic acid copolymer, about 12% (w/w) talc, and about 8%(w/w) triethyl citrate, wherein the weight percentage is based on theweight of the enteric coat.